Have you ever tried Calibrachoa? Here is a link to read about them, if you scroll down once getting there, you'll see many links for many different varieties:
http://www.bhg.com/gardening/plant-dictionary/annual/calibrachoa/
They are listed as annuals, but if you live in a milder climate they will come back sometimes. I'm not sure where you are located. Anyway, I live where we get snow & ice in the Winter, and these flowers are great because they are easy to grow, don't have to be babied constantly, and come in many beautiful colors & varieties, even striped. I just love 'em, because they are almost always blooming from Spring until late Fall!
My mother never liked Azaeleas because she said although they are beautiful when they bloom, the rest of the year she didn't like the way the leaves looked on the plant, so she would never plant them for that reason. That matters less with a big planting area in a huge yard, but if a person only has a small garden, they really want to love everything they plant.
Good luck with your project, it sounds like fun!
I'll add some pictures of various Calibrachoa, then I'll add pics of Coleus, which are leafy plants that are very colorful & come in many different varieties:


Calibrachoa come in many different colors, from red to purple, blue to yellow, and multi-colored.
Coleus varieties:

Several different varieties of coleus ^^^

Red & Green Coleus

Purple Coleus

The above Coleus (last one) is called "Ruby Laser."
☼SerenityNow!☼
"Be as a bird perched on a frail branch that she feels bending beneath her; still she sings away all the same, knowing she has wings." ~Victor Hugo